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Bayram is the Turkiс word for a nationally celebrated
festival or holiday, applicable to both national (i.e. secular) or
religious celebrations. In accordance with this dual applicability,
the method with which one determines the yearly timing of Bayrams
is different for national and religious holidays.

State
holidays in Turkey have set dates under the nationally-used Gregorian Calendar, while the religious
holidays are coordinated and publicly announced in advance by the
Government's Presidency
of Religious Affairs department according to the Lunar Calendar, and are subsequently
accommodated into the national Gregorian Calendar, which results in
the dates for religious holidays changing every year with a shift
margin of approximately 11 days.

Large scale non-Turkish or non-Islamic traditions and celebrations
may similarly be called Bayram, as illustrated by Halloween being referred to as "Cadılar Bayramı"
(i.e. "Bayram of Witches"), Easter as
"Paskalya Bayramı" (i.e. "Easter Bayram") or "Hamursuz Bayramı"
("No-flour Bayram", used by Jews), Christmas as "Noel Bayramı" (i.e. "Christmas
Bayram"), or Hanukkah as "Yeniden Adanma
Bayramı" (i.e. "Renewal/Rededication Bayram"). However, it should
be noted that not every special occasion or holiday is referred to
as a Bayram, as illustrated by the case of New Year's Eve, World Health Day or Liberation of Istanbul, among others.
Also many Albanian and Bosnian Muslims refer to Eid ul-Fitr as Bayram, most likely because both
countries were part of the Ottoman Empire for many years.